Electric furnace



April 30. 1929. H. ELDRIDGE ELECTRIC FURNACE Filed May 19, 1925 3 Sheets-Sham l @hun um* April 30, 1929. H. ELDRIDGE ELECTRIC FURNACE Filed may 19I 1925 5 Sheets-Sheet Eltbozwaq April 30, 1929. I H, ELDRIDGE 1,711,088

ELECTRI C FURNACE Filed may 19'. v1925 5 sheets-sheet 3 Patented Apr.' 30, 19.29.

HILLIARY ELDRIDGE, OF OAKLAND, CALIFORNIA, ASSIGNOR, BY MESNE .SSIGN- MENTS, AND CDURT ORDER, TO MARTHA K.

ELDRID GE.

ELECTRIC4 EURNACE.

" Application mea may 1e, 1925. serial No. 31,391.

The present invention relates to improvements' in an apparatus forand a process of [producing calcium carbide, and its principal object is to provide an improved furnace for producing calcium carbide from a mixture of lime and carbon Which, at the same time has features embodied therein y which allow the Waste heatas Well as the products of combustionto be utilized fortreating other materials, such as shale, so that liquid hydrocarbons may be gained from the shale as a by-product inthe process of manufacturing calcium carbide. This latter feature is all the more advantageous because shale can ordinarily not be turned into liquid hydro-carbons at an advantage due` to the high cost of fuel, while in my improved apparatus there is practically no extra expense connected with t-he treatment of the shale While, furthermore, after treatment there remains a residueof carbon Which can be used as one of the constituents of calcium carbide.'

When subjecting a mixture of lime and carbon to an electric arc, carbon monoxide Ais released, and it is .the object ofmy invention to not only utilize the heat radiated from the furnace for heating` `retorts containing shale,

but to also inject a supporter of combustion, such as atmospheric air, into the' carbon v monoxide so as to allow the same to combust and give additional heat While torts containing the shale.

For a convenient arrangement a plurality of retorts may be provided some of which passing the remay be filled with shale While others may be lled Withcoal for the production of coal gas which may be utilized in calcining lime stone for the production of lime, the other constituent of calcium carbide, so that Where my improved process and apparatus are eriployed, calcium carbide and liquid hydrocarbons may be rapidly andcheaply produced ina single combination process Wherever a deposit oflime stone and of shale is available, in addition to a limited amount of coal.

In addition to the general arrangement of my apparatus for the purposes se't forth heremabove, I provide specific features Which render' my apparatus particularly adapted to perform its functions and for easy handling of the materials employed.

The preferred form lof my apparatus is shown in the accompanying drawings, 1n which Figure 1 shows a vertical section through i the same.

Figure 2 a horizontal section taken along line 2 2 of Figure 1.

Figure 3 a horizontal section taken substantially along line 3 3 of Figure 1. v

Figure 4 a sectional detail View taken along line 4-4 of Figure -1. l

Figure 5 a vertical section through a modified form of furnace, and 1 Figure 6 a horizontal section taken along line 6-6 of Figure 5.

Vhile I have shown only the `preferred forms of my invention,-I Wish to have it nnderstood that various changes or modifications may be made Within the scope of the claims hereto attached Without departingfrom the spirit of the invention.

My furnace as illustrated in Figures-l to 4 includes as its principal parts an, elevated side Wall structure 11 made of refractory material and resting on any suitable frame 12 leaving the space` below 'the side structure -clear to accommodate the portable bottom 13 of the furnace. The latter comprises a truck 14 adapted to ride on the rails 1G having a central projection 17 rising therefrom and the body 18 of the bottom Which is formed With a central cavity 19 and has a sleeve 21 depending therefrom Which telescopes over the projection 17 While a shaft 22 is threaded into the projection and bears through balls 23 Aon the underface of the body of the furnace bottom so that the latter inay be raised and lowered at will by turning the shaft 22, the

turning motion being executed by means of a handle 24. Y

It will be seen that in this manner the body of the bottom can be brought in intimate contact With the stationary side Wall structure by raising the body, the top edge of the latter fitting into an annular flange 26 depending from the platform 27 on which the side Wall structure rests and the opening of the cavity at the top being coextensive with the opening in the side Wall structure.

At the top the side Wall structure is closed by means of a plurality of blocks 27 of insulating material heldin place by a metal ring 28 surrounding the same, which latter is bolted as shown at 29 to a supporting plate 31 resting on the side Wall structure, While the blocks 27 rest on ledges 82 formed in the refractory material and are conined at the top by angle irons 33. Centrally supported with freedom of sliding motion in the top members 27 is a carbon electrode 34, the lower end of which extends into the cavity of the bottom 13, and the lower blocks 27 are recessed around the carbon electrode as shown at 36 to allow material to be vfed into the furnace from the hopper 37 through the pipe 38 byy means of the conveyor 39which is driven from the motor 41.v The carbon electrode 34 issupported in the clamp illustratedin detail in Figure 3, consisting of a horizontal arm 42 recessed near its free end as shown at V 43 to encompassa peripheral section of the stantially` parallel relation. Each of the armsl is provided' with a Water cooled chamber 49 adjacent the carbon electrode through which Water may be passed through the pipes 51 A and 52.

The arm 42 is supported to always maintain a horizontal position but with freedom of vertical adjustability by riding on two vertical shafts 53 spaced from one another and rising from anv insulating block 45 secured to the top plate 31 while motion may be imparted to Athe arm through the threaded rod` 56 engaging the same as at 57 which latter rod has a gear wheel 591 keyed thereto as shown at 61 with a worm'62, illustrated 1n Figure 4, imparting rotar'lmotion to the'gear wheel 59 when the han revolved.

The carbon electrode 34 extends into the e 63' is manually cawilzy of the bottom portion 13 while a second electrode 64 is supported in the body of the removable bottom section. The latter is for this purpose provided with a port 66- which may serve as a discharge` `ort for the treated material and which is c osed by the insertion ofthe carbonelectrode, both ort .and electrode being preferably tapered in a manner illustrated in Figure 1, and the electrode vbeing .forced intoplace through the Watercooled conducting element 67 which has the head 68 of the pin 69 threaded there- 'into and which is advanced b means of a nut 71 in the frame 72, the nut eing-separated from the conducting element 67 and the pin 69 by means of two insulators 73 yand 74. A wire 76 is secured to the pin 69 as shown at 77 andtheother line wire 78 is secured to the varm 42 as shown at 79. The frame 72 is preferably pivotally secured to stationa brackets 81 extending from the body of t e portable bottom as shown at 82 so that when it is desired to remove the carbon electrode, it is only necessary to loosen the nut 71 and to turnw the frame 72 on its hinge whereupon the'carbon electrode may be pulled out.

The stationary refractory side wall of the furnace is preferably built to present in horizont-al section a plurality of wings 83 each of which is recessed radially relative to the furnacepropervas shown at 84 and accommodates in the recess a retort 86 accessible from the outside by removal of the cover 87 clamped upon its open'vend by means of a screw 88 threaded into a yoke 89 braced against the inner face of' a flange 91. Each recess communicates at its outer end with a flue 92through which the products of combustion from the furnace may escape. Each -of the recesses also has a pipe 93 preferably made of porcelain leading thereinto in such a manner that air forced through the pipe by means of a.pump not shown in the drawing is discharged in the' recess in the direction of travel of the products of combustion atthe inner end of the retort, as shown at 94. The retorts aie'provided with suitable outlet pipes 96 which lead to a suitable condenser, preferably of fractional condenser type.

The operation of the device may be described as follows: n

A' mixture of lime and carbon is fed into the hopper 33 land is conveyed throuvh the pipe 38 into kthe bottom cavity 19. ln arc formed between the two electrodes converts the mixture into calcium carbide and during the process carbon monoxide is released as one of the products ofthe combustion. .Heat is radiated from the furnace and passes through the recesses 84 and past the retorts 86 into the flues 92. Before the gases forming the product of combustion in the lfurnace pass the retort, air is forced into the same and allows the carbon monoxide to be combustedl lto providea'dditional heat units for the retorts 86. a

Any ldesired number of retorts may be provided and I preferably use most of them for the distillation of shale, the retorts being filled with shale at suitable intervals andthe heat serving to distill hydro-carbon gases from the solid material which gases may be guided through the pipe 96 into a fractional condens er for the production of oils Vof various degrees. As a residue, carbon remains in the lretort and may beutilizedeither for-the manufacture of-carbon` electrodes or for mixture with lime in the. hopper 37 for production of v calcium carbide. One of the retorts is' preferably used for distillation of coal for the production of coal as and hydro-carbon vapors adapted to be utilized in the calcining of calcium .carbonate into lime which forms the other constituent of the calcium carbide, while the carbon resultin from the distillation of the coal may also le used as a constituent ofthe calcium carbide.

'When the process is.com leted relative to one batchof calcium 'carbi e, the bottom 13 may be lowered, the' truck pushed forward after the vertical carbon electrode 34 has been raised and a new truck and bottom may be substituted whereupon the process may be continued immediately. vAfter the truck has been removed, the -nut 71 may be unscrewed Awhereby the conducting element 67 is sepawhich alturned on its hinge 64 to be removed so 'rated from the carbon electrode 64 lows the frame 72to be and the carbon electrode as to establish an outlet for the contentsof the cavity.

In Figures 5 and 6 is shown a slightly dif- 1. The retorts 101 instead of radiating rom a common center` are arranged parallel to the sides of the rectangular furnace in recesses 102 provi-dedA for the same with flues 103 communicating with the recesses at their upper ends. A charge is delivered into the furnace through the pipe 104 in a manner similar to that previously described. The-retorts may be arranged so that they maybe opened at'either end as shown at 106 in Figure 6'.

In addition to supporting the combustion of the carbon monoxide gas, the current of atmospheric air traveling under the retort in the direction ofthe furnace outletscreates a pull or suction on the carbon monoxide gas as 1t is produced in the calcium carbide reaction, with the result that the pressure of the reaction is kept reduced to a minimum and an increased production of calc ium'car bide is accomplished through the fact that the reaction proceeds continuously for reverse reaction' cannot take place if an equilibrium of pressure is prevented by constant exhaustion of pressure.

While in the preceding description referenceis had to the manufacture of calcium carbide, the outstanding features of my process and of my apparatus may be used to the same therewith,

advantage in the manufacture of aluminum and cast steel or iron.

I claim:

1. In an electric furnace of the character described, a stationary side wall structure having an electrode extending thereinto, a

portable bottom formed with acentral cavity having means for raising the side walls thereof into intimate contact with the stationary side wall associated therewith and being formed with a discharge port communicating a second electrode nordischarge port for closwith the cavity and mally disposed in the ing the same.

2. In-an electric furnace of the character described,- a stationary side wall structure having an electrode extending thereinto, a portable bottom formed with a central cavity having means for raising the side walls thereof into intimate contact with the stationary side wall associated therewith and being formed with a tapered discharge port communicating With the cavity, and a tapered electrode" adapted to close the discharge port having means connected therewith for positively driving the same into the exhaust port.

'3. In an Aelectric furnace of the character described, a stationary elevated side wall structure, aportable furnace bottom having means for raising the same into intimate cor.- tact with the side wall structure associated means for feeding material through the side wall structure into the bottom, electrodes arranged to provide a gap within the said bottom, and retorts arranged in the side walls of thc `stationary structure so as to cause products of combustion to pass the same.

4. In an electric furnaceyof thecharacter described, a 'stationary elevated side wall structure, a portable furnace bottom having means for raising the same into intimate Contact with the side wally structure associated therewith, means for feeding material through the'side wall structure'into the bottom, electrodes arranged to provide a gap within the said bottom, and retorts arranged in the side Walls of the stationary structure vso as to cause products of combustion to 

